KR100715956B1 - Screw rotor machine having means for axially biasing at least one of the rotors - Google Patents

Abstract

The present invention relates to a rotor machine, in particular a helical screw rotor machine, wherein the rotor machine comprises at least one rotor with trunnions, at least one of the trunnions being filled with a working medium (17). And an axial thrust face 29 positioned within and driven axially by the working medium. The working medium chamber must be connected to the trunnion 7 in a sealed state. This is achieved according to the invention by arranging the casings 20, 21 with the outer ends connected with the bottom wall 21 with the holes 22 in the center, by interference fit around the trunnions. The casing is rotatably and slidably mounted to the trunnion so that the bottom wall 21 has an end wall of the chamber 17 with an opening 24 disposed opposite the center hole 22 of the bottom wall. Axially moveable between a first axial position in contact with 23 and a second axial position with a space between the bottom wall 21 and the end wall 23, the valve 27 A supply channel 26 is provided and extends from the working medium source 28 to the opening 24 of the end wall 23 so that the working medium opens the holes 22 of the bottom wall 21 of the casing. It is conveyed while being controlled into the casing (20, 21) through.

Description

A screw rotor machine having a means for pressing at least one of the rotors in an axial direction. (SCREW ROTOR MACHINE HAVING MEANS FOR AXIALLY BIASING AT LEAST ONE OF THE ROTORS)

TECHNICAL FIELD The present invention relates to a rotor machine, and more particularly, to a helical rotor machine of a type defined in the preamble of claim 1.

The rotor machine, when designed to act as a compressor, compresses the working medium to a higher pressure level, whereas when designed to expand the working medium, the working medium expands from the elevated pressure level. For the sake of brevity in the description, only the former case, i.e., the case where the rotor machine acts as a compressor, is described, but the following description applies to the same extent as for the case of inflating the working medium.

In the case of helical screw rotor compressors, the working medium is compressed in a V-shaped working chamber. In the filling step, each work chamber is in communication with an inlet port located at the low pressure end. When communication with the inlet port is interrupted, the rotation of the rotor causes the working chamber to move towards the high pressure end, resulting in a decrease in the volume of the working chamber, thereby compressing the working medium contained in the working chamber. When the working chamber is moved axially toward the high pressure end to the extent that communication with the outlet port is initiated, an evacuation phase is initiated, during which the volume of the working chamber continues to decrease, forcing the working medium through the outlet port at a high pressure level. Discharged. Thus, the rotor is exposed to higher pressure at the high pressure end than at the low pressure end, which means that each rotor is thrust in the low pressure end direction. This thrust is absorbed by thrust bearings mounted on one or both of the low and high pressure ends.

Some working medium leaks from the high pressure end around the trunnion and enters the bearing chamber at the high pressure end. In order to ensure that the interior of the bearing chamber is not at a high pressure level equivalent to the outlet pressure, a relief channel is provided in the work chamber for returning the working medium to a closed work chamber where the predetermined level of pressure is slightly higher than the inlet pressure. Is common. The relief channel also serves to circulate oil through the rotor bearings. As a result, the pressure in the bearing chamber becomes the pressure level in the closed working chamber. This pressure exerts a force on the end face of the rotor trunnion and is also directed to the low pressure end of the compressor.

The axial force acting on the rotor due to the pressure difference between the low pressure end and the high pressure end varies in magnitude during the compression step and the rotor contacts each other because of the contact between the groove and the flank face of the lobe. It is distributed differently in the rotor. The distribution of forces acting in this axial direction also changes during the compression phase. Thus, the axial force acting on each rotor is pulsated. When the compressor is operated at full load, the axial force generated by the working medium is large enough so that the force on each rotor always faces the low pressure end, even if the magnitude of the force changes.

Typically, in this type of compressor, the load is reduced by greatly throttling the inlet pressure to approximately 0.1 bar while lowering the outlet pressure to approximately half of the outlet pressure at full load.

As mentioned above, when the compressor is driven without load, the axial force acting on the rotor in the low pressure end direction becomes smaller, in part because the pressure difference between the outlet pressure and the inlet pressure is smaller, It is also partly due to the lower pressure in the bearing chamber at the high pressure end. In this connection, because of the pulsation of the force described above, there is a risk that the axial force is not large enough so that the force on each rotor is always directed to the low pressure end. Thus, the force on the rotor can change in sign momentarily and act in the high pressure end direction. This causes one or both of the rotors to vibrate in the axial direction. Then, rattling occurs as the flanks of the rotor collide with each other. These shocks damage the rotor and shorten the life of the bearings.

The rattling problem can be solved by applying an axial force to one or both of the rotors toward the low pressure end of the compressor, but due to the large load on the thrust bearing of the rotor when the rotor is acting axially from the high pressure side The problem can be solved by applying an axial force in the high pressure side direction of the rotor machine to one or both of the rotors.

It is an object of the present invention to simply and reliably reduce the large axial force applied to the thrust bearing of a helical rotor machine, or by applying an axial force acting in the same or opposite direction to the gas pressure acting through compression to the rotor. In other words, the partial load is used to offset the rattling.

This object has been achieved by the present invention, in the rotor machine of the type defined at the outset, the outer end having a generally circular cylindrical outer surface, freely disposed in the chamber, and closed by a bottom wall with a hole in the center. A casing having an interference fit around one trunnion, the casing being rotatably mounted and having a first axial position where the bottom wall is spaced apart from the end wall of the chamber, and the bottom wall being Can move axially on the trunnion over a given distance between a second axial position in contact with an end wall of the chamber and move the casing from the first axial position to the second axial position while creating an overpressure inside the casing. Supplying the working medium to move the working medium into the casing through the holes in the bottom wall of the casing for movement. The mount supply channel extending from the valve is connected to an opening in the end wall disposed opposite to the center hole of the bottom wall.

In one preferred embodiment, a ring sealing element is arranged between the end wall and the bottom wall surface of the casing facing the end wall, the ring sealing element having a diameter smaller than the diameter of the portion of the trunnion surrounded by the casing. Form a circular sealing line.

Other advantageous embodiments will be apparent from the dependent claims.

According to the invention, since pressure fluid can be supplied into the casing surrounding the end of the trunnion, the casing is pressed against the end wall mainly by dynamic pressure from the fluid. In the case of a ring sealing element, the contact pressure against the end wall depends on how small the diameter of the sealing line is than the diameter of the trunnion pressure surface. One advantageous situation is that the casing adjusts its radial position through the position of the trunnion, and when the supply of the working medium is stopped, the pressing of the casing against the end wall stops, thus rubbing between the casing and the end wall or trunnion. The casing can begin to rotate with the trunnion without loss.

The invention will now be described in more detail with reference to the accompanying drawings, with reference to various exemplary embodiments of the construction of the invention.

1 is a longitudinal sectional view of a helical screw compressor according to one embodiment of the present invention.

2 is a fragmentary longitudinal cross-sectional view of the casing mounted to the trunnion against the end wall;

FIG. 3 is a cross sectional view similar to FIG. 2 except that the casing is removed from the end wall; FIG.

4 is a cross sectional view similar to FIG. 2 except that the sealing ring is mounted to the end wall;

5 is a longitudinal sectional view of a casing adapted for mounting an extended trunnion;

The compressor shown in FIG. 1 is for air compression and includes a water rotor 1 and an arm rotor 2 which are typically provided with a helically extending lobe and grooves (not shown), and through the lobes and grooves. Thus, the water rotor 1 and the arm rotor 2 mesh with each other to form a working chamber in the work space 3 of the compressor. The work space 3 is bounded by a low pressure end 4 and a high pressure end 5 and a barrel portion 6 extending therebetween, the barrel portion 6 being parallel to each other in parallel. It has a cylindrical shape. Each end of the rotor is provided with trunnions 7, 8, 9, 10 supported at the bearings 11, 12, 13, 14 at two ends, respectively.

The compressor has an inlet port 15 at the low pressure end and an outlet port 16 at the high pressure end. The bearing at the low pressure end 4 is located in the bearing chamber 17 at a predetermined pressure P2. The compressor is of the so-called wet type, ie a liquid, usually oil, is supplied to the compressor for the purpose of cooling, lubricating and sealing the compressor.

At full load, the compressor operates at the same inlet pressure as atmospheric pressure, and the compressed air leaves the compressor at a pressure of approximately 8 bar. The pressure difference between the inlet and outlet ends of the compressor results in an axial force acting in the low pressure end direction for each of the rotors 1, 2. Usually this force is absorbed by the thrust bearings 12, 14 located at the high pressure end 5.

According to the present invention, in order to reduce the load of the bearing 12, a casing with the cylindrical portion 20 and the bottom wall 21 is provided with an interference fit around the trunnion 7 end. The casings 20, 21 are located in the chamber 17, the interior of the casing communicates with the chamber through the opening 22 in the center of the bottom wall 21, and the bottom wall 21 is in the chamber 17. ) Is parallel to the end wall 23 for closing the opening, and an opening 24 facing the hole 22 of the bottom wall 21 is formed in the center. The bottom wall 21 of the casing converges toward the central hole 22 of the casing inside. The bottom wall 21 is provided with a ring-shaped sealing element 25, the opening 24 of the end wall 23 is provided with a valve 27 and forms a supply channel extending from the working medium source 28. The means 26 are connected. The working medium source 28 may be an oil separator and the working medium may be oil.

By opening the valve 27 and introducing the working medium from the working medium source 28 through the conduit means 26 to the casings 20, 21 via the openings 24 and the holes 22. Of the load is reduced.

The incoming working medium exerts dynamic pressure inside the casing, thereby moving the casing into sealing contact with the end wall 23 by the sealing element 25.

The working medium source 28 generates a pressure P1 within the casing that is greater than the pressure P2 in the chamber 17.

The sealing element 25 is circular and forms a closed sealing line, the area enclosed by the closed sealing line being smaller than the end face 29 of the trunnion 7, which means that the diameter D1 of the sealing line It can be seen well from FIG. 2 that is slightly smaller than the diameter of the trunnion and therefore smaller than the inner diameter D2 of the casings 20 and 21. Thus, the working medium with the pressure P1, on the one hand, partially exerts a force on the inner wall of the casing to press the casing against the end wall 23 and on the other hand to the end face 29 of the trunnion 7. Is applied to force the water rotor 1 toward the high pressure end 5 while reducing the load on the bearing 12.

In the illustrated case, the trunnion 7 rotates in the casings 20 and 21 in the non-rotating state, which is cascaded radially to the correct position by the trunnion 7. Thereafter, when the valve 27 is closed, the pressure P1 inside the casings 20 and 21 drops, so that the casing comes into contact with the end wall 23, and the pressure inside the casing stops at ambient pressure P2. Becomes the same as The casing then starts to rotate with the rotation of the trunnion 7, thus eliminating all friction and wear of the casing and trunnion 7 as is apparent from FIG. 3. As shown in Fig. 4, the casing 20, 21 is prevented from colliding with the end wall 23 by providing the ring-shaped magnetic devices 40, 41 which repel each other in the casing 20, 21 that rotates.

As shown in FIG. 4, the circular sealing element 25 may be attached to the end wall 23 instead of the bottom wall 21 of the casing for convenience. In the latter case, it is possible to facilitate replacement of the worn sealing element 25 by attaching the sealing element to the bushing 42 which can be screwed from the outside into the end wall for convenience.

The present invention can also be applied to the case where the trunnion 30 extends through the shaft seal 32 attachment hole 31 in the end wall 23, as shown in FIG. 5.

In the case of the embodiment shown in FIG. 5, if one wants to obtain a pressure surface of the same area as the end face 29 of the trunnion 7 of FIG. 2, the diameter of the trunnion 30 using the thrust collar 35 is used. It is necessary to form a ring-shaped end face 29 'that protrudes in the axial direction with the same area as the end face 29 of FIG. As described above, the casing 33 is mounted to the thrust collar 35 by interference fit. The end wall 23 has an opening 34 formed around the trunnion seal 32, which receives a pipe 36 in communication with a source of working medium (not shown). The casing 33 includes a cylindrical portion 37 and a bottom portion 38, and the bottom portion 38 has a central hole large enough in diameter to allow the opening 34 to discharge inward from around the central hole 39. 39 is formed.

If the present invention intends to remove the latling, the casings 20 and 21 are fitted to the ends of the trunnion 10 in the same manner as described above, and the opening 34 is adjacent as shown by the dashed line in FIG. Place it on the end wall.

It is to be understood that the invention is not limited to the foregoing embodiments by way of example, and that various modifications are possible within the scope of the invention as defined in the claims. For example, the casings 20 and 21 can be made of a flat elastic material outside the bottom wall 21 so that a sealing action can be obtained without a separate sealing element. The same can be applied to the interior of the end walls 23 facing the casings 20 and 21. According to the present invention, it is natural that the load reduction means can also be provided in the trunnion 9.

If the internal pressure of the casing 20, 21 or 33, which co-rotates with the trunnion, is the same as the pressure acting from the outside, the casing 20 (Fig. 4) in FIG. As shown in connection with 21, on the end wall 23 and each of the bottom walls 21 and 38 of the casing, they are temporarily rebounded to maintain the necessary interspace between the end wall and the bottom wall of the casing. It is possible to provide ring-shaped magnets 40, 41 arranged and magnetized to contribute.

Claims (9)

The at least one rotor 1 provided with trunnions 7, 8 comprises a housing surrounded by a work space 3 comprising an inlet port 15 and an outlet port 16, wherein the work space ( 3) is delimited by a low pressure end 4, a high pressure end 5 and a barrel 6 extending between these two ends, the trunnions 7 and 8 being connected to both ends 4 and 5; A thrust surface 29 which extends into the bearings 11, 12 at which at least one of the trunnions extends through the corresponding end 4 and protrudes axially within the delimited chamber 17. In the rotor machine for compressing or inflating a working medium, the chamber (17) receives means for generating an axially acting force on the thrust surface (29). Around the one trunnion 7, the casing 20, 21, whose outer surface is generally circular-cylindrical and freely disposed in the chamber 17, whose outer end is closed by the bottom wall 21, is forcibly fitted. And a hole 22 in the center of the bottom wall, the casing is rotatably mounted on the trunnion, and the bottom wall 21 is an end wall 23 of the chamber 17. Axially along the trunnion over a given distance between a first axial position spaced apart from the second axial position where the bottom wall 21 is in contact with the end wall 23. A moving medium to move the casing from the first axial position to the second axial position while creating an overpressure in the casing 20, 21. 22 through the casing 20, 21 In order to regulate supply to the negative side, an end wall 23 having a valve 27 and extending from the working medium source 28, disposed opposite the center hole 22 of the bottom wall 21. A rotor machine, connected to the opening 24 of the rotor. A ring-shaped sealing element (25) is located between the end wall (23) and the bottom wall (21) of the casing facing the end wall (23). A rotor machine characterized by forming a circular sealing line having a diameter smaller than the portion of the trunnion (7) surrounded by the casing (20). 3. Rotor machine according to claim 2, characterized in that the sealing element (25) is fixed to the bottom wall (21) of the casing. 3. Rotor machine according to claim 2, characterized in that the sealing element (25) is fixed to the end wall (23). 4. Rotor according to claim 3, characterized in that the sealing element (25) is mounted to a bushing (42) which can be inserted from the outside into the end wall (23) and in which an opening (24) for working medium supply is arranged. machine. The rotor machine according to any one of claims 1 to 5, wherein the bottom wall (21) of the casing converges inward toward the central hole (22) of the casing. 6. Rotor machine according to any one of the preceding claims, characterized in that the end walls (23) and the bottom walls (21) are provided with magnetic elements (40, 41) which repel each other, respectively. 6. The rotor machine according to claim 1, wherein the working medium is oil and the working medium source is an oil separator connected with the rotor machine. 7. The rotor machine of claim 1, wherein the rotor machine is a helical screw rotor machine.

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